This invention relates to night vision imaging systems in general, and more particularly to an aviator's night vision imaging system particularly adapted to be selectively mounted on a helmet.
The term night vision imaging system can be interpreted broadly enough to encompass such disparate items as matches and flashlights at one extreme, to pulse illuminated, range gated, low light television systems at the other extreme. Such systems include direct viewing systems employing image intensification. These systems have various uses as commercial as well as military applications, but in general, enable night time vision by responding to low level radiation which is present at night as, for example, to reflected light emanating from the stars or the moon. The techniques are also applicable to viewing objects at night, which objects emit heat or infra-red radiation, which radiation can be detected by night vision imaging techniques.
Such devices conventionally employ an image intensifier or similar structure. The function of the intensifier is to multiply the amount of incident light received by it to provide a greater signal for application to a camera or directly to the eyes of a user. Examples of early uses of such devices can be had by reference to a text entitled "Photo Electricity and Its Applications" published in 1948 by John Wiley & Sons. Chapter 18 entitled "Light Beam Signaling and Infra-red Detection" shows examples of early night vision imaging systems such as the "Sniperscope" and "Snooperscope". These devices are employed by the military to enable troops to perceive the enemy at night, but as indicated, many non-military applications are applicable.
There have been significant strides made in the development of night vision imaging systems enabling the fabrication of devices which are relatively compact and reliable. Hence, various companies as the Assignee herein, provide a number of devices such as night vision goggles and other imaging systems for night time viewing. Indicative of such systems is the apparatus depicted in U.S. Pat. No. 4,202,601 entitled TRAINING AID FOR USE WITH NIGHT VISION APPARATUS, issued on May 13, 1980 to J. H. Burbo and L. P. Hartman and assigned to the Assignee herein. This patent depicts a night vision goggle assembly which is secured to the head of a user by means of a strap and enables a user to perceive at night with great acuity and perception. Such goggles are manufactured by ITT Electro-Optical Products Division of Roanoke, Virginia and designated as No. F-4921. These goggles are employed in military applications or in other specified activities such as flying aircraft, driving or weapons operations.
Other devices manufactured by ITT as F-4923 include night vision goggles for aviators. These goggles include a night viewing system having image intensifier tubes combined with plastic optics and are adapted to be secured to a flight helmet using hook tape and snap fasteners or can be worn on the head by the use of standard headstraps.
Based on extensive use of such devices, it has been determined that the night imaging system is extremely desirable, but there is an absolute need, expecially for use in aviation, to intimately and reliably integrate the imaging system with the helmet. In prior art devices, such as the above noted goggles, the pilot could not easily remove, adjust or otherwise conveniently employ the goggles, while operating the aircraft. Hence, the goggles were employed in limited operations and did not provide the user with the versatility required. The requirements imposed by flying an aircraft or otherwise manipulating any vehicle under stress conditions, impose formidable factors in the implementation of a compatible night vision imaging system operating in conjunction with a helmet. These factors must consider the practical application of human engineering principles, coupled with skillful optical, mechanical and electrical engineering to provide a night vision device that is efficient and useful to the population of aviators who will fly with it. Major factors in such design are associated with the difficult requirement of maintaining the weight of such apparatus to a minimum; a necessary factor in regard to aviation equipment.
It is therefore an object of the present invention to provide an improved night vision imaging system adapted to be mounted on a helmet, which combination of apparatus provides extreme versatility to a user, such as a pilot, to enable optimum use of the apparatus under extreme stress conditions.